Adhesive tape, battery cell, and battery

Abstract

The utility model discloses a kind of adhesive paper, battery cell and battery, wherein adhesive paper includes: base layer and adhesive layer.Adhesive layer is connected to the surface of base layer, the first bonding surface of the surface of adhesive layer away from base layer, adhesive layer has bonding groove, bonding groove extends to first bonding surface along the thickness direction of adhesive paper, and first opening is formed in first bonding surface, bonding groove has with the first inner wall towards first opening, and with the second inner wall and the second bonding surface intersect, define first inner wall as second bonding surface.Second inner wall is third bonding surface;Wherein, first bonding surface is used to bond with current collector, bonding groove is used for pole ear to extend into, and the surface of pole ear is respectively bonded with second bonding surface and third bonding surface. Thus, not only can adhesive paper better with current collector fit, and adhesive paper can be bonded with the side of pole ear, increase the bonding area of adhesive paper, so that adhesive paper is more firmly bonded on current collector and pole ear, to improve the safety of battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an adhesive tape, a battery cell, and a battery. Background Technology

[0002] In batteries, after the tabs are welded to the current collector, adhesive tape needs to be applied to the tab welding position to prevent the weld burrs from puncturing the separator. In order to improve the energy density of the battery, the size of the adhesive tape is getting smaller and smaller. However, the reduction in the size of the adhesive tape leads to a corresponding reduction in the adhesive area, which increases the risk of the adhesive tape falling off, thereby reducing the safety of the battery. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an adhesive tape that can more firmly adhere to the electrode tab welding position, reducing the risk of falling off and thus improving battery safety.

[0004] This invention also provides a battery cell comprising the aforementioned adhesive paper.

[0005] This utility model also provides a battery including the above-mentioned battery cell.

[0006] According to a first aspect of the present invention, an adhesive tape is used to adhere to a current collector and cover the electrode tab welding position, the adhesive tape comprising: a base layer and an adhesive layer.

[0007] The adhesive layer is attached to one surface of the base layer along the thickness direction of the adhesive paper. The surface of the adhesive layer facing away from the base layer is a first bonding surface. The adhesive layer has an adhesive groove extending along the thickness direction of the adhesive paper to the first bonding surface and forming a first opening on the first bonding surface. The adhesive groove has a first inner wall facing the first opening and a second inner wall intersecting the first inner wall and the second bonding surface. The first inner wall is defined as the second bonding surface. The second inner wall is a third bonding surface. The first bonding surface is used for bonding with the current collector, and the adhesive groove is used for the insertion of the electrode tab, allowing the surface of the electrode tab to bond with both the second and third bonding surfaces.

[0008] The adhesive tape according to the embodiments of this utility model has at least the following beneficial effects:

[0009] In this embodiment, the adhesive tape not only has a first adhesive surface for bonding with the current collector, but also an adhesive groove. The inner wall of the adhesive groove forms a second adhesive surface and a third adhesive surface. When the adhesive tape of this embodiment is used to cover the tab welding position, the tab and the current collector welding part are located in the receiving groove. The second adhesive surface is bonded to the surface of the tab opposite to the tab, and the third adhesive surface is bonded to the side of the tab. Therefore, compared with conventional technology, the tab being located in the adhesive groove not only allows the adhesive tape to better adhere to the current collector, but also allows the adhesive tape to bond to the side of the tab. Thus, without changing the width of the adhesive tape, the bonding area of ​​the adhesive tape can be increased, making the adhesive tape more firmly bonded to the current collector and the tab, thereby reducing the risk of the adhesive tape falling off and improving battery safety.

[0010] According to some embodiments of the present invention, the melting point of the adhesive layer is lower than that of the base layer, and the adhesive layer is capable of melting.

[0011] The battery cell according to the second aspect of the present invention includes an electrode sheet, an electrode tab, and an adhesive tape according to the first aspect of the present invention.

[0012] The electrode includes a current collector having an empty foil area; the electrode tab includes a welding portion welded to the empty foil area, the surface of the welding portion facing away from the empty foil area being a first surface, the surface of the welding portion intersecting with the first surface and located between the empty foil area and the first surface being a second surface; the first adhesive surface of the adhesive tape is bonded to the empty foil area, the welding portion is located in the adhesive groove, the second adhesive surface is bonded to the first surface, and the third adhesive surface is bonded to the second surface.

[0013] The battery cell according to the embodiments of this utility model has at least the following beneficial effects:

[0014] The adhesive tape using the first aspect embodiment has an adhesive groove, the inner wall of which forms a second adhesive surface and a third adhesive surface, and the welding part is located in the adhesive groove. This not only allows the adhesive tape to better adhere to the current collector, but also allows the adhesive tape to adhere to the side of the electrode tab. Therefore, without changing the width of the adhesive tape, the adhesive area of ​​the adhesive tape can be increased, making the adhesive tape more firmly adhered to the current collector and the electrode tab, thereby reducing the risk of the adhesive tape falling off and improving the safety of the battery.

[0015] According to some embodiments of the present invention, the welded part has a receiving groove, and a portion of the adhesive layer is embedded in the receiving groove and bonded to the inner wall of the receiving groove.

[0016] According to some embodiments of the present invention, the receiving groove is inclined relative to the thickness direction of the welded part, the melting point of the adhesive layer is lower than the melting point of the base layer, and the adhesive layer can melt and flow into the receiving groove.

[0017] According to some embodiments of the present invention, a gap is defined between the welding part and the empty foil area, and an opening communicating with the gap is provided. The melting point of the adhesive layer is lower than the melting point of the base layer, and the adhesive layer is capable of melting and flowing into the gap from the second opening.

[0018] According to some embodiments of the present invention, the side of the welding part facing the empty foil area has a first groove, and the inner wall of the first groove forms the gap with the empty foil area;

[0019] The first groove extends to the edge of the welded portion to form the second opening; or,

[0020] The welded portion has a second opening, which extends through the welded portion along its thickness direction.

[0021] According to some embodiments of this utility model, the surface of the welded portion opposite to the first surface is a third surface, and the first groove is formed by the welded portion through material removal on the third surface; or...

[0022] The first groove is formed by embossing the welded portion on the third surface; or,

[0023] The first groove is formed by stamping a portion of the welded portion along the direction from the third surface to the first surface, and a first protrusion is formed on the first surface.

[0024] According to some embodiments of this utility model, the adhesive layer is a conductive adhesive.

[0025] The battery according to a third aspect embodiment of the present invention includes: the battery cell according to the second aspect embodiment.

[0026] The battery cell according to the embodiments of this utility model has at least the following beneficial effects:

[0027] In the battery cell using the second aspect embodiment, the adhesive tape in the battery cell has an adhesive groove, and the inner wall of the adhesive groove forms a second adhesive surface and a third adhesive surface. The welding part is located in the adhesive groove. This not only allows the adhesive tape to better adhere to the current collector, but also allows the adhesive tape to adhere to the side of the electrode tab. Therefore, without changing the width of the adhesive tape, the adhesive area of ​​the adhesive tape can be increased, making the adhesive tape more firmly adhered to the current collector and the electrode tab, thereby reducing the risk of the adhesive tape falling off and improving the safety of the battery.

[0028] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0030] Figure 1 This is a schematic diagram of the structure of the adhesive paper according to the first aspect of this utility model;

[0031] Figure 2 This is a schematic diagram of the structure of the first type of battery cell according to the second aspect of the present invention;

[0032] Figure 3 for Figure 1 A partial cross-sectional view of the battery cell;

[0033] Figure 4 This is a partial cross-sectional view of a second type of battery cell according to a second aspect embodiment of the present utility model;

[0034] Figure 5 This is a partial cross-sectional view of a third type of battery cell according to a second aspect embodiment of the present utility model;

[0035] Figure 6 This is a partial cross-sectional view of the fourth type of battery cell according to the second aspect of the present invention;

[0036] Figure 7 This is a partial cross-sectional view of the fifth type of battery cell according to the second aspect of the present invention;

[0037] Figure 8 This is a partial cross-sectional view of the sixth type of battery cell according to the second aspect of this utility model.

[0038] Figure label:

[0039] 1000 pieces of adhesive tape;

[0040] 100 at the grassroots level;

[0041] Adhesive layer 200, first adhesive surface 201, second adhesive surface 202, third adhesive surface 203, adhesive groove 210, first inner wall 211, second inner wall 212, first opening 220, second protrusion 230, connecting post 240;

[0042] The electrode tab 300, the welding part 310, the first surface 311, the second surface 312, the receiving groove 313, the third surface 314, the first protrusion 315, and the first groove 316;

[0043] Current collector 400, empty foil area 410;

[0044] Gap 500, second opening 600, electrode 700. Detailed Implementation

[0045] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0046] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0047] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0048] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0049] In batteries, after the tabs are welded to the current collector, adhesive tape needs to be applied to the tab welding position to prevent the weld burrs from puncturing the separator. In order to improve the energy density of the battery, the size of the adhesive tape is getting smaller and smaller. However, the reduction in the size of the adhesive tape leads to a corresponding reduction in the adhesive area, which increases the risk of the adhesive tape falling off, thereby reducing the safety of the battery.

[0050] In view of the above background, referring to Figures 1 to 3 The first aspect of this utility model is an adhesive tape 1000, which is used to adhere to the current collector 400 and cover the welding position of the electrode tab 300. The adhesive tape 1000 includes: a base layer 100 and an adhesive layer 200.

[0051] The base layer 100 is made of one or more of polyester (PET), polyimide (PI), or polypropylene (PP), which gives the adhesive tape 1000 a certain strength. The adhesive layer 200 is made of one or more of the following: acrylic acid, silicone, rubber, ethylene-vinyl acetate copolymer (EVA), polyamide (PA), or polyolefin (PO). The adhesive layer 200 is attached to one surface of the base layer 100 in the thickness direction of the adhesive paper 1000. The surface of the adhesive layer 200 facing away from the base layer 100 is the first bonding surface 201. The adhesive layer 200 has an adhesive groove 210 that extends along the thickness direction of the adhesive paper 1000 to the first bonding surface 201 and forms a first opening 220 in the first bonding surface 201. The adhesive groove 210 has a first inner wall 211 facing the first opening 220 and a second inner wall 212 that intersects with the first inner wall 211 and the second bonding surface 202. The first inner wall 211 is defined as the second bonding surface 202. The second inner wall 212 is the third adhesive surface 203; wherein, the first adhesive surface 201 is used to bond with the current collector 400, and the adhesive groove 210 is used to allow the tab 300 to extend into, and to bond the surface of the tab 300 to the second adhesive surface 202 and the third adhesive surface 203 respectively.

[0052] Specifically, the adhesive tape 1000 described in the first aspect of this utility model is used for the protection of the welding position of the lithium battery tab 300, and is composed of a base layer 100 and an adhesive layer 200. The base layer 100 is, for example, a high heat-resistant polymer material such as polyimide (PI) or polyethylene terephthalate (PET), which provides structural support and shape retention for the adhesive tape 1000; the adhesive layer 200 is attached to one side of the base layer 100 by a coating process, and its exposed surface forms a first adhesive surface 201 for bonding the lithium battery current collector 400.

[0053] The adhesive layer 200 has an adhesive groove 210 extending along the thickness direction of the adhesive paper 1000 to the first adhesive surface 201, and the groove forms an opening structure on the first adhesive surface 201. The adhesive groove 210 includes a first inner wall 211 facing the opening (defined as the second adhesive surface 202) and a second inner wall 212 perpendicularly intersecting the first inner wall 211 (defined as the third adhesive surface 203). During the lithium battery assembly process, the welding part 310 of the tab 300 can be embedded in the adhesive groove 210, so that the top surface of the tab 300 forms a surface contact bond with the second adhesive surface 202, and the side surface forms a surface contact bond with the third adhesive surface 203.

[0054] Compared to the limitations of traditional flat adhesive tape 1000, which can only form a single-sided bond with the top surface of tab 300, the adhesive tape 1000 in this embodiment, through the design of a three-dimensional adhesive groove 210, can achieve a three-dimensional wrapping and bonding of tab 300 without increasing the lateral dimension of adhesive tape 1000. This significantly increases the bonding area between adhesive tape 1000 and tab 300, effectively disperses the peeling stress generated by the thermal expansion of tab 300 during battery charging and discharging, reduces the risk of internal short circuit caused by welding burrs piercing the separator due to adhesive tape 1000 falling off, and greatly improves the safety of lithium battery packaging.

[0055] In this embodiment, the adhesive tape 1000 not only has a first adhesive surface 201 for bonding with the current collector 400, but also has an adhesive groove 210. The inner wall of the adhesive groove 210 forms a second adhesive surface 202 and a third adhesive surface 203. When the adhesive tape 1000 of this embodiment is used to cover the welding position of the tab 300, the tab 300 and the welding part 310 of the current collector 400 are located in the receiving groove. The second adhesive surface 202 is bonded to the surface of the tab 300 away from the tab 300, and the third adhesive surface 203 is bonded to the side of the tab 300. Therefore, compared with traditional technology, the tab 300 is located in the adhesive groove 210, which not only allows the adhesive tape 1000 to better adhere to the current collector 400, but also allows the adhesive tape 1000 to adhere to the side of the tab 300. Thus, without changing the width of the adhesive tape 1000, the bonding area of ​​the adhesive tape 1000 can be increased, making the adhesive tape 1000 more firmly bonded to the current collector 400 and the tab 300, thereby reducing the risk of the adhesive tape 1000 falling off and improving battery safety.

[0056] In some embodiments, the melting point of the adhesive layer 200 is lower than that of the base layer 100. The adhesive layer 200 can melt and bond the tabs 300 and the current collector 400. The adhesive layer 200 is, for example, made of low-melting-point ethylene-vinyl acetate copolymer (EVA), and the base layer 100 is, for example, made of polyethylene terephthalate (PET), which has a higher melting point. In the lithium battery hot-pressing encapsulation process, the adhesive layer 200 is heated and melted to form a fluid state. For example, in the battery hot-pressing encapsulation process, the adhesive layer 200 is heated and melted to form a fluid state, allowing the adhesive layer 200 to come into more complete contact with the tabs 300 and the current collector 400, and even penetrating into the tiny pores on the surface of the tabs 300 and the current collector 400. This further enhances the bonding strength between the adhesive tape 1000 and the tabs 300 and the current collector 400, effectively preventing the adhesive tape 1000 from falling off when the battery is subjected to complex operating conditions such as vibration and impact, thereby improving battery safety and service life.

[0057] Reference Figure 2 and Figure 3According to a second aspect embodiment of the present invention, the battery cell is, for example, a laminated battery cell or a wound battery cell, and includes an electrode 700, a tab 300, and an adhesive tape 1000 as described in the first aspect embodiment. The electrode 700 is, for example, an anode plate and a cathode plate, and includes a current collector 400, which has an empty foil area 410. The tab 300 is, for example, a positive tab 300 and a negative tab 300. The tab 300 includes a welding part 310, which is welded to the empty foil area 410. The surface of the welding part 310 facing away from the empty foil area 410 is a first surface 311, and the surface of the welding part 310 intersecting with the first surface 311 and located between the empty foil area 410 and the first surface 311 is a second surface 312. The first adhesive surface 201 of the adhesive tape 1000 is bonded to the empty foil area 410, the welding part 310 is located in the adhesive groove 210, the second adhesive surface 202 is bonded to the first surface 311, and the third adhesive surface 203 is bonded to the second surface 312. This not only allows the adhesive tape 1000 to better adhere to the current collector 400, but also enables the adhesive tape 1000 to adhere to the side of the tab 300. Therefore, without changing the width of the adhesive tape 1000, the bonding area of ​​the adhesive tape 1000 can be increased, making the adhesive tape 1000 more firmly bonded to the current collector 400 and the tab 300, thereby reducing the risk of the adhesive tape 1000 falling off and improving battery safety.

[0058] It should be noted that since the battery cell of this embodiment includes all the technical features of the adhesive tape 1000 of the first aspect embodiment, this embodiment has all the beneficial effects brought by the first aspect embodiment, which will not be repeated here.

[0059] Reference Figure 4In some embodiments, the welding portion 310 has a receiving groove 313, and a portion of the adhesive layer 200 is embedded in the receiving groove and bonded to the inner wall of the receiving groove 313. Specifically, the receiving groove 313 is formed on the surface of the welding portion 310 of the tab 300 by stamping, etching, or embossing. The shape of the receiving groove 313 is, for example, U-shaped, V-shaped, or dovetail-shaped. The receiving groove 313 is formed, for example, before welding with the current collector 400, and the welding torch avoids the location of the receiving groove 313 during welding, or it is formed on the welding portion 310 after welding is completed. The adhesive layer 200 has a second protrusion 230 of a corresponding shape and is embedded in the receiving groove 313 and bonded to the inner wall of the receiving groove 313. This not only increases the bonding area between the adhesive layer 200 and the tab 300, but also forms a mechanical interlocking structure, thereby further improving the bonding strength of the adhesive tape 1000. This allows the adhesive tape 1000 to adhere more firmly to the current collector 400 and the tab 300, thereby reducing the risk of the adhesive tape 1000 falling off and improving battery safety. The second protrusion 230 can be formed before the adhesive tape 1000 is bonded to the tab 300, or, as in some embodiments, the melting point of the adhesive layer 200 is lower than that of the base layer 100. After the adhesive tape 1000 is bonded to the tab 300, the adhesive layer 200 is melted by hot pressing and flows into the receiving groove 313 to form the protrusion.

[0060] Reference Figure 5 In some embodiments, the receiving groove 313 is inclined relative to the thickness direction of the welded portion 310, and the melting point of the adhesive layer 200 is lower than that of the base layer 100, allowing the adhesive layer 200 to melt and flow into the receiving groove 313. Specifically, since the receiving groove 313 is inclined relative to the thickness direction of the tab 300, after the molten adhesive layer 200 flows into the receiving groove 313 and cools and solidifies, it forms an anchoring structure that can prevent the first adhesive tape 1000 from moving along the thickness direction of the tab 300. That is, the risk of the adhesive tape 1000 falling off can be reduced, thereby further improving the safety of the battery.

[0061] Similarly, refer to Figure 6 and Figure 7In some embodiments, a gap 500 is defined between the welding portion 310 and the empty foil area 410, and a second opening 600 communicating with the gap 500. The melting point of the adhesive layer 200 is lower than that of the base layer 100, and the adhesive layer 200 can melt and flow into the gap 500 from the second opening 600. For example, in some embodiments, the empty foil area 410 of the current collector 400 is formed with a second groove by laser processing or embossing, and the welding portion 310 partially covers the second groove, thereby forming the gap 500 and the second opening 600. In yet another embodiment, the side of the welding portion 310 facing the empty foil area 410 has a first groove 316, the inner wall of the first groove 316 forms a gap 500 with the empty foil area 410, and the first groove 316 extends to the edge of the welding portion 310 to form the second opening 600 (e.g., Figure 6 (As shown). Alternatively, the weld portion 310 has a second opening 600 that extends through the weld portion 310 along its thickness direction (as shown). Figure 7 (As shown). Thus, the molten adhesive layer 200 can flow into the gap 500 from the second opening 600, and after the adhesive layer 200 cools and solidifies, it can form a connecting post 240 that penetrates the second opening 600 and is connected at both ends. This not only restricts the movement of the adhesive tape 1000 in the thickness direction of the tab 300, but also restricts the movement of the adhesive tape 1000 in the width and length directions of the tab 300, thereby improving the adhesion strength of the adhesive tape 1000 in this embodiment and thus improving battery safety.

[0062] Furthermore, it is understood that in the battery field, the thickness of the tab 300 is typically greater than the thickness of the current collector 400. Therefore, forming the first groove 316 on the tab 300 is simpler than forming the second groove on the current collector 400, thereby reducing processing difficulty and cost. For example, in some embodiments, the surface of the welding portion 310 opposite to the first surface 311 is the third surface 314, and the first groove 316 is formed by the welding portion 310 on the third surface 314 using a material removal process such as laser processing or etching. Alternatively, as in some embodiments, the first groove 316 is formed by the welding portion 310 embossing on the third surface 314. Embossing is more efficient and less costly than etching and laser processing, and causes less damage to the material, reducing the risk of tab 300 breakage. In yet another embodiment, the first groove 316 is formed by stamping a portion of the welding portion 310 along the direction from the third surface 314 to the first surface 311, and a first protrusion 315 is formed on the first surface 311 (e.g., Figure 8(As shown). That is, in this embodiment, not only can a first groove 316 be formed on the third surface 314, but a first protrusion 315 can also be formed on the first surface 311. The first protrusion 315 can increase the contact area between the tab 300 and the adhesive tape 1000, enhance the welding strength, and further improve the overall performance and stability of the battery.

[0063] In some embodiments, the adhesive layer 200 is a conductive adhesive, such as a silver-based or copper-based conductive adhesive. This conductive adhesive not only bonds the adhesive tape 1000 to the current collector 400 and the tab 300, but also, after melting, flows into the gap 500 between the welding part 310 and the current collector 400, thereby forming a conductive connection. This enhances current transmission efficiency, reduces resistance loss, and further improves the battery's range and stability. Simultaneously, the fluidity of the conductive adhesive ensures uniform filling of the gap 500, preventing localized overheating, further optimizing battery thermal management, and extending service life.

[0064] According to a third aspect embodiment of the present invention, the battery is, for example, a steel-cased battery, an aluminum-cased battery, or a pouch battery, and includes the cell of the second aspect embodiment. The adhesive tape 1000 in the cell has an adhesive groove 210, the inner wall of which forms a second adhesive surface 202 and a third adhesive surface 203. A welding portion 310 is located within the adhesive groove 210. This not only allows the adhesive tape 1000 to better adhere to the current collector 400, but also allows the adhesive tape 1000 to adhere to the side of the tab 300. Therefore, without changing the width of the adhesive tape 1000, the adhesive area of ​​the adhesive tape 1000 can be increased, making the adhesive tape 1000 more firmly adhered to the current collector 400 and the tab 300, thereby reducing the risk of the adhesive tape 1000 falling off and improving battery safety.

[0065] It should be noted that since the battery in this embodiment adopts all the technical features of the second aspect embodiment, this embodiment has all the beneficial effects brought by the second aspect embodiment, which will not be repeated here.

[0066] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, in the description of the present invention, the reference to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. Adhesive tape, characterized in that, For bonding to the current collector and covering the electrode tab welding position, including: grassroots level; An adhesive layer is attached to a surface of the base layer in the thickness direction of the adhesive paper. The surface of the adhesive layer facing away from the base layer is a first bonding surface. The adhesive layer has an adhesive groove that extends along the thickness direction of the adhesive paper to the first bonding surface and forms a first opening on the first bonding surface. The adhesive groove has a first inner wall facing the first opening and a second inner wall that intersects with the first inner wall and the second bonding surface. The first inner wall is defined as the second bonding surface, and the second inner wall is defined as the third bonding surface. The first adhesive surface is used to bond with the current collector, and the adhesive groove is used to allow the electrode tab to extend into, so that the surface of the electrode tab is bonded to the second adhesive surface and the third adhesive surface respectively.

2. The adhesive tape according to claim 1, characterized in that, The adhesive layer has a lower melting point than the base layer, and the adhesive layer is capable of melting.

3. A battery cell, characterized in that, include; An electrode, comprising a current collector having an empty foil region; The electrode tab includes a welding part, which is welded to the empty foil area. The surface of the welding part facing away from the empty foil area is a first surface, and the surface of the welding part intersecting with the first surface and located between the empty foil area and the first surface is a second surface. The adhesive tape according to claim 1 or 2, wherein the first adhesive surface of the adhesive tape is bonded to the empty foil area, the welding part is located in the adhesive groove, the second adhesive surface is bonded to the first surface, and the third adhesive surface is bonded to the second surface.

4. The battery cell according to claim 3, characterized in that, The welded part has a receiving groove, and a portion of the adhesive layer is embedded in the receiving groove and adhered to the inner wall of the receiving groove.

5. The battery cell according to claim 4, characterized in that, The receiving groove is inclined relative to the thickness direction of the welded part, and the melting point of the adhesive layer is lower than that of the base layer, so that the adhesive layer can melt and flow into the receiving groove.

6. The battery cell according to claim 3, characterized in that, A gap is defined between the welded portion and the empty foil area, and a second opening communicates with the gap. The melting point of the adhesive layer is lower than that of the base layer, and the adhesive layer can melt and flow into the gap from the second opening.

7. The battery cell according to claim 6, characterized in that, The welding part has a first groove on the side facing the empty foil area, and the inner wall of the first groove forms the gap with the empty foil area; The first groove extends to the edge of the welded portion to form the second opening; or, The welded portion has a second opening, which extends through the welded portion along its thickness direction.

8. The battery cell according to claim 7, characterized in that, The surface of the welded portion opposite to the first surface is a third surface, and the first groove is formed by the welded portion through material removal from the third surface; or... The first groove is formed by embossing the welded portion on the third surface; or, The first groove is formed by stamping a portion of the welded portion along the direction from the third surface to the first surface, and a first protrusion is formed on the first surface.

9. The battery cell according to claim 8, characterized in that, The adhesive layer is a conductive adhesive.

10. A battery, characterized in that, The battery cell includes any one of claims 3 to 9.

Images